Lawmakers in New Hampshire approved a bill Wednesday that would repeal the state's gay marriage law, which will not affect same-sex couples already married, only prevent new couples from marrying if it goes into effect.

The amended bill, HB 427, will define marriage as only between a man and woman, and will allow civil unions between both heterosexual and homosexual couples competent to enter into a contract.

State Rep. David Bates, who sponsored the amended bill, said the civil union law strictly for same-sex couples treats homosexuals as a special group.

"There was no rational reason to limit that to same-sex couples," said Bates, R-Windham, according to the Associated Press (AP).

New Hampshire is one of only six states that recognize same-sex marriage, along with Iowa, New York, Massachusetts, Vermont, District of Columbia and Connecticut.

The law took effect in January 2010, but the committee voted to hold off on dealing with the matter until the following legislative session. Both the House and Senate are majority Republican and it is believed lawmakers will approve the amended bill.

Tyler Deaton of Standing Up for New Hampshire Families, a coalition that supports the gay marriage law, believes the bill discriminates against homosexuals by allowing individuals to treat the unions as invalid if they violate their religious beliefs.

"You can have a civil union, but it's meaningless," he told the AP.

New Hampshire Gov. John Lynch said he would veto any attempts to repeal the law, which he signed in 2009, the AP reported.

More than 1,500 New Hampshire gay couples have married so far under the current law.

The bill faces a vote by the full committee next month and the House in January 2012.